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Implementation And Validation Of Quadratic Constitutive Relation In One Equation K Kl Turbulence Model
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Book Synopsis Implementation and Validation of Quadratic Constitutive Relation in One-equation K-kL Turbulence Model by : Hanfeng Zhang (Mechanical engineer)
Download or read book Implementation and Validation of Quadratic Constitutive Relation in One-equation K-kL Turbulence Model written by Hanfeng Zhang (Mechanical engineer) and published by . This book was released on 2020 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid Dynamics (CFD) has been widely used in modern engineering analysis of products and systems involving fluid flow. In majority of applications, the flow is turbulent; however accurate prediction of turbulent flow remains a challenging problem to date. Considering both the accuracy and cost of simulations, the most widely used approach for simulation of turbulent flows is to solve the Reynolds Averaged Navier-Stokes equations (RANS) in conjunction with a turbulence model which models the Reynolds stresses using the Boussinesq approximation that relates the Reynolds stress tensor to strain tensor via an eddy viscosity. In past many decades, a linear relationship between Reynolds Stress tensor and strain tensor has been employed in almost all turbulence models. Linear eddy viscosity models have shown good results for wide variety of flows; however in many cases they have been found to be inadequate. Therefore, the nonlinear Quadratic Constitutive Relation (QCR) has been suggested to improve the accuracy of simulations. In this thesis, QCR is implemented for a recently developed one-equation k-kL turbulence model by Shuai and Agarwal, and is tested by comparing its accuracy with linear eddy viscosity models and one-equation Algebraic Reynolds Stress Model (ARSM) developed by Wen and Agarwal. The computational results for k-kL-QCR for several benchmark cases from NASA TMR are compared to other widely used turbulence models with QCR, such as Spalart-Allmaras model (SA), Wray-Agarwal model (WA) and SST k-[omega] model. It is shown that one-equation k-kL-QCR model shows good accuracy against experimental data with less computational cost for both incompressible and compressible transonic and supersonic flow cases.
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781794002876 Total Pages :32 pages Book Rating :4.0/5 (28 download)
Book Synopsis Verification and Validation of the K-Kl Turbulence Model in Fun3d and Cfl3d Codes by : National Aeronautics and Space Adm Nasa
Download or read book Verification and Validation of the K-Kl Turbulence Model in Fun3d and Cfl3d Codes written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The implementation of the k-kL turbulence model using multiple computational uid dy- namics (CFD) codes is reported herein. The k-kL model is a two-equation turbulence model based on Abdol-Hamid's closure and Menter's modi cation to Rotta's two-equation model. Rotta shows that a reliable transport equation can be formed from the turbulent length scale L, and the turbulent kinetic energy k. Rotta's equation is well suited for term-by-term mod- eling and displays useful features compared to other two-equation models. An important di erence is that this formulation leads to the inclusion of higher-order velocity derivatives in the source terms of the scale equations. This can enhance the ability of the Reynolds- averaged Navier-Stokes (RANS) solvers to simulate unsteady ows. The present report documents the formulation of the model as implemented in the CFD codes Fun3D and CFL3D. Methodology, veri cation and validation examples are shown. Attached and sepa- rated ow cases are documented and compared with experimental data. The results show generally very good comparisons with canonical and experimental data, as well as matching results code-to-code. The results from this formulation are similar or better than results using the SST turbulence model. Abdol-Hamid, Khaled S. and Carlson, Jan-Renee and Rumsey, Christopher L. Langley Research Center NASA-TM-2015-218968, NF1676L-22522, L-20609
Book Synopsis Development and Application of Quadratic Constitutive Relation and Transitional Crossflow Effects in the Wray-Agarwal Turbulence Model by : Hakop J. Nagapetyan
Download or read book Development and Application of Quadratic Constitutive Relation and Transitional Crossflow Effects in the Wray-Agarwal Turbulence Model written by Hakop J. Nagapetyan and published by . This book was released on 2018 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid Dynamics (CFD) has now become an almost indispensable tool for modern engineering analysis of fluid flow over aircrafts, turbomachinery, automobiles, and many other industrial applications. Accurate prediction of turbulent flows remains a challenging problem. The most popular approach for simulating turbulent flows in complex industrial applications is based on the solution of the Reynolds-Averaged Navier-Stokes (RANS) equations. RANS equations introduce the so called "Reynolds or turbulent stresses" which are generally modeled using the Boussinesq approximation known as "Turbulence modeling." Despite their development over a century, the turbulence models used with RANS equations still need much improvement. The first part of this research introduces the Quadratic Constitutive Relations (QCR), which is a nonlinear approach to approximating the turbulent stresses in eddy-viscosity class of turbulence models. In Boussinesq approximation, turbulent stresses are assumed to be linearly proportional to the strain with eddy viscosity being the proportionality constant. In recent years it has been found that linear eddy viscosity models are not accurate for prediction of vortical flows and wall bounded flows with mild separation with regions of recirculating flows. Such flows occur in junctions of aerodynamic surfaces e.g. the wing-body junction and in inlets and ducts with corners. The accurate prediction of these flows is needed for design improvements and better product performance. To remedy some of the shortcomings of the linear eddy-viscosity models, the Quadratic Constitutive Relation (QCR) for eddy viscosity is investigated to test its capability for predicting non-equilibrium turbulence effects. QCR is implemented in Spalart-Allmaras (SA), SST k-[omega] and Wray-Agarwal (WA) turbulence models and is applied to several applications involving large recirculating regions. It is demonstrated That QCR improves the results compared to linear eddy viscosity models. Another shortcoming of RANS models is their inability to accurately predict regions of transitional flow in a flow field. Many flow regions in industrial applications contain the transitional flow regime e.g. flows over aircraft wings and fuselages, past wind turbines and in gas turbines engines to name a few. The second part of this research has been on the development of a transitional model by suitably combining a correlation based intermittency-[gamma] equation with the WA turbulence model; this new model is designated as Wray-Agarwal-[gamma] (WA-[gamma]) transition model. The WA-[gamma] is extensively validated by computing a number of benchmark cases. The WA-[gamma] model is also extended to include the crossflow-instability induced transition which is a dominant mode of transition in flows involving three-dimensional boundary layers, e.g. flow past swept wings and ellipsoids. This modified WA-[gamma] model is validated using a benchmark test case for analyzing crossflow-induced transition.
Book Synopsis Development and Validation of a One-Equation Turbulence Model by : B. Aupoix
Download or read book Development and Validation of a One-Equation Turbulence Model written by B. Aupoix and published by . This book was released on 1998 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Implementation and Validation of the Chien K-epsilon Turbulence Model in the Wind Navier-Stokes Code by :
Download or read book Implementation and Validation of the Chien K-epsilon Turbulence Model in the Wind Navier-Stokes Code written by and published by . This book was released on 1999 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Implementation of Two-equation Turbulence Models in U2NCLE by : Vishwas Shringi
Download or read book Implementation of Two-equation Turbulence Models in U2NCLE written by Vishwas Shringi and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the study of two-equation turbulence modeling. The primary objective of this study is to implement two-equation k-[epsilon] and k-[omega] turbulence models as a part of the incompressible flow solver, U2NCLE, on unstructured grids. There are several two-equation models but the selection of one which is in par with the model in UNCLE solver is required so that this model can be compared for robustness and accuracy as demonstrated by turbulence models in UNCLE. The selection also requires that the pre-defined arrays and variables can be used to avoid overhead and deviation from the solution procedure used in U2NCLE. The present study deals with the two-equation k-[epsilon] model contributed by Shih and Lumley and the two-equation k-[omega] model contributed by Wilcox. Implementation of these models will give the user multiple options of two-equation turbulence modeling for solution purpose. Particular attention is paid to the efficiency of the implementation. Various approximations to the source terms are considered and the most optimal and accurate approximation is identified. These models are validated via relatively small model problems, for example a flat plate case, by comparing the results with the results obtained from the respective models in UNCLE and the existing two-equation q-[omega] model in U2NCLE. Further validation is carried out by comparing computed forces and moments with experimental data for SUBOFF model with sail and stern appendages.
Book Synopsis Implementation of a Two-equation K-[omega] Turbulence Model in NPARC by : Dennis Yoder (A.)
Download or read book Implementation of a Two-equation K-[omega] Turbulence Model in NPARC written by Dennis Yoder (A.) and published by . This book was released on 1996 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Implementation of a Two-equation K-w Turbulence Model in NPARC by : Dennis A. Yoder
Download or read book Implementation of a Two-equation K-w Turbulence Model in NPARC written by Dennis A. Yoder and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Implementation and Validation of the Chien K-e Turbulence Model in the WIND Navier-Stokes Code by : Dennis A. Yoder
Download or read book Implementation and Validation of the Chien K-e Turbulence Model in the WIND Navier-Stokes Code written by Dennis A. Yoder and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of the K-Epsilon Turbulence Model by : B. Mohammadi
Download or read book Analysis of the K-Epsilon Turbulence Model written by B. Mohammadi and published by . This book was released on 1994-09-06 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aimed at applied mathematicians interested in the numerical simulation of turbulent flows. Centered around the k-&epsis; model, it also deals with other models such as one equation models, subgrid scale models and Reynolds Stress models. Presents the k-&epsis; method for turbulence in a language familiar to applied mathematicians, but has none of the technicalities of turbulence theory.
Book Synopsis Turbulence Modeling for CFD: CD-ROM by : David C. Wilcox
Download or read book Turbulence Modeling for CFD: CD-ROM written by David C. Wilcox and published by . This book was released on 2006 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Computational Fluid Dynamics by : Jiri Blazek
Download or read book Computational Fluid Dynamics written by Jiri Blazek and published by Elsevier. This book was released on 2005-12-20 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid Dynamics (CFD) is an important design tool in engineering and also a substantial research tool in various physical sciences as well as in biology. The objective of this book is to provide university students with a solid foundation for understanding the numerical methods employed in today’s CFD and to familiarise them with modern CFD codes by hands-on experience. It is also intended for engineers and scientists starting to work in the field of CFD or for those who apply CFD codes. Due to the detailed index, the text can serve as a reference handbook too. Each chapter includes an extensive bibliography, which provides an excellent basis for further studies.
Download or read book Scale Invariance written by Annick LESNE and published by Springer Science & Business Media. This book was released on 2011-11-04 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: During a century, from the Van der Waals mean field description (1874) of gases to the introduction of renormalization group (RG techniques 1970), thermodynamics and statistical physics were just unable to account for the incredible universality which was observed in numerous critical phenomena. The great success of RG techniques is not only to solve perfectly this challenge of critical behaviour in thermal transitions but to introduce extremely useful tools in a wide field of daily situations where a system exhibits scale invariance. The introduction of scaling, scale invariance and universality concepts has been a significant turn in modern physics and more generally in natural sciences. Since then, a new "physics of scaling laws and critical exponents", rooted in scaling approaches, allows quantitative descriptions of numerous phenomena, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos and turbulence. The chapters are jointly written by an experimentalist and a theorist. This book aims at a pedagogical overview, offering to the students and researchers a thorough conceptual background and a simple account of a wide range of applications. It presents a complete tour of both the formal advances and experimental results associated with the notion of scaling, in physics, chemistry and biology.
Book Synopsis The Finite Element Method: Theory, Implementation, and Applications by : Mats G. Larson
Download or read book The Finite Element Method: Theory, Implementation, and Applications written by Mats G. Larson and published by Springer Science & Business Media. This book was released on 2013-01-13 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives an introduction to the finite element method as a general computational method for solving partial differential equations approximately. Our approach is mathematical in nature with a strong focus on the underlying mathematical principles, such as approximation properties of piecewise polynomial spaces, and variational formulations of partial differential equations, but with a minimum level of advanced mathematical machinery from functional analysis and partial differential equations. In principle, the material should be accessible to students with only knowledge of calculus of several variables, basic partial differential equations, and linear algebra, as the necessary concepts from more advanced analysis are introduced when needed. Throughout the text we emphasize implementation of the involved algorithms, and have therefore mixed mathematical theory with concrete computer code using the numerical software MATLAB is and its PDE-Toolbox. We have also had the ambition to cover some of the most important applications of finite elements and the basic finite element methods developed for those applications, including diffusion and transport phenomena, solid and fluid mechanics, and also electromagnetics.
Download or read book Modelling Fluid Flow written by János Vad and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling Fluid Flow presents invited lectures, workshop summaries and a selection of papers from a recent international conference CMFF '03 on fluid technology. The lectures follow the current evolution and the newest challenges of the computational methods and measuring techniques related to fluid flow. The workshop summaries reflect the recent trends, open questions and unsolved problems in the mutually inspiring fields of experimental and computational fluid mechanics. The papers cover a wide range of fluids engineering, including reactive flow, chemical and process engineering, environmental fluid dynamics, turbulence modelling, numerical methods, and fluid machinery.
Book Synopsis Mathematical and Numerical Foundations of Turbulence Models and Applications by : Tomás Chacón Rebollo
Download or read book Mathematical and Numerical Foundations of Turbulence Models and Applications written by Tomás Chacón Rebollo and published by Springer. This book was released on 2014-06-17 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: With applications to climate, technology, and industry, the modeling and numerical simulation of turbulent flows are rich with history and modern relevance. The complexity of the problems that arise in the study of turbulence requires tools from various scientific disciplines, including mathematics, physics, engineering and computer science. Authored by two experts in the area with a long history of collaboration, this monograph provides a current, detailed look at several turbulence models from both the theoretical and numerical perspectives. The k-epsilon, large-eddy simulation and other models are rigorously derived and their performance is analyzed using benchmark simulations for real-world turbulent flows. Mathematical and Numerical Foundations of Turbulence Models and Applications is an ideal reference for students in applied mathematics and engineering, as well as researchers in mathematical and numerical fluid dynamics. It is also a valuable resource for advanced graduate students in fluid dynamics, engineers, physical oceanographers, meteorologists and climatologists.
Book Synopsis Computational Engineering - Introduction to Numerical Methods by : Michael Schäfer
Download or read book Computational Engineering - Introduction to Numerical Methods written by Michael Schäfer and published by Springer Nature. This book was released on 2021-07-19 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical simulation methods in all engineering disciplines gains more and more importance. The successful and efficient application of such tools requires certain basic knowledge about the underlying numerical techniques. The text gives a practice-oriented introduction in modern numerical methods as they typically are applied in mechanical, chemical, or civil engineering. Problems from heat transfer, structural mechanics, and fluid mechanics constitute a thematical focus of the text. For the basic understanding of the topic aspects of numerical mathematics, natural sciences, computer science, and the corresponding engineering area are simultaneously important. Usually, the necessary information is distributed in different textbooks from the individual disciplines. In the present text the subject matter is presented in a comprehensive multidisciplinary way, where aspects from the different fields are treated insofar as it is necessary for general understanding. Overarching aspects and important questions related to accuracy, efficiency, and cost effectiveness are discussed. The topics are presented in an introductory manner, such that besides basic mathematical standard knowledge in analysis and linear algebra no further prerequisites are necessary. The book is suitable either for self-study or as an accompanying textbook for corresponding lectures. It can be useful for students of engineering disciplines as well as for computational engineers in industrial practice.
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